Can you feel it? The change in the air? It’s undeniable…winter is taking over. Your bikinis are already feeling neglected and you probably won’t touch your sunscreen tube for the next few months... Big mistake! Skin experts align on this: to avoid cumulative damages on the skin, SPF must be used all-year-round.

The sun may feel weaker or even absent in winter…but that doesn’t mean skin-damaging UV rays are not hitting your skin. UVA rays, in particular, are present all-year-round. Photo: Autri Theri (Unsplash.com)

The sun may feel weaker or even absent in winter…but that doesn’t mean skin-damaging UV rays are not hitting your skin. UVA rays, in particular, are present all-year-round. For this reason, wearing sunscreen throughout the year - even in the coldest months - is critical for those who want to keep your skin looking younger for longer. To fully understand it, here is a little refresher on UVA and UVB rays.

UVA | Ultraviolet A rays, also called "long wave" rays, make up 95 percent of the rays that reach the surface of the Earth. They can penetrate the skin much deeper than UVB rays, and are responsible for signs of aging (like dark spots and wrinkles). They also can initiate skin cancers. These are the rays that make you more tan (ref: gq.com). UVA rays can penetrate glass and clouds – you are thus likely to be exposed to UVA rays all year round, even in the shade and indoors.

UVB |Ultraviolet B rays, or "shortwave" rays, don’t penetrate the skin as deeply. They're what causes redness and sunburns. They are most intense from early spring to early fall, and during the day’s sunniest hours. UVB rays are not as likely to penetrate glass as UVA rays, but even though they dwindle in the winter, many can reach the Earth’s surface and are easily reflected off snow and ice. This makes them a bigger threat on the ski slopes, and at higher altitudes on sunny days (ref: gq.com). If you are hitting the slopes this winter, remember that reflection from snow can increase UV radiation by up to 50%, and increases by 15% for every kilometre in altitude.​

Even though they dwindle in the winter, many UVB rays can reach the Earth’s surface and are easily reflected off snow and ice. This makes them a bigger threat on the ski slopes, and at higher altitudes on sunny days. Photo: Mattias Olsson (Unsplash.com).

Dermatologists recommend the use of a broad-spectrum sunscreen on a daily basis and all year round, to prevent cumulative damages caused by sun exposure, such as fine lines, wrinkles, discoloration and even skin cancer. According to Dr. Jean Laing, founder of the spa brand LaGaia Unedited, "most people underestimate the dangers of UV-exposure in winter, and associate sun-damage to sun-burn only. UVA rays are the most insidious because they hit the skin unseenand cause cumulative impacts over time". In essence, "if there is a shadow, there is UVA, even indoors!" To mitigate their effects, Dr. Jean Laing recommends wearing SPF daily – as part of your morning skin routine. “Sunscreen is your #1 sun and ageing control…You may not see it now, but in 10 to 20 years you will see a huge difference in your skin”. ​

We humans have lost our natural barriers against harmful UV-rays...Fur, dust and mud use to be our sun-screens. Today, our skin's health depends on the use of protective clothing and creams. Corals on the other hand, had to come up with a better solution to withstand the damaging effects of excessive sun exposure. Corals are a complex mix of plant and animal...they start their life as larvae floating in the water column, but eventually have to settle for life on the reef - ideally somewhere sunny - as they require the energy of the sun to grow into large coral colonies. Being stationary animals, corals can't take shelter from the sun when they've had enough of it, or apply sunscreen during the strong hours of the sun...Or is there something we can’t see? Something hiding under the surface?

​When shining a special type of light on the reef, corals reveal colours that cannot be seen with the naked eye. They become fluorescent under UV-light (or more commonly known as black light). For many years, we enjoyed the beauty of coral flurorescence without really knowing it's origin and importance. In the 2000's, studies revealed that fluorescence may actually be a way for corals to protect their skin from the sun (Roth et al., 2006). Special proteins within the coral tissue are responsible for synthesising a layer of fluorescent pigments (called FP layer) that - very much like an inbuilt sunscreen - is capable of regulating the amount of light that the coral is exposed to in a process called photo-protection.

Corals "inbuilt sunscreen" is invisible to the naked eye (left) but can be revealed under ultra violet light (right). photo: Bob Yin

​In excessive sunlight, the FP layer is able to dissipate excess energy into wavelengths, restoring suitable condition for photosynthesis and healty coral function. It is also believed that fluorescent proteins can help corals through period of heat stress by reducing oxidative stress within the coral tissue, thus keeping corals from bleaching for longer periods (Roth et al., 2006; Shalin et al., 2000; Bou-Abdallah et al., 2006). During a bleaching event, the fluorescent layer becomes visible under normal light as all other pigments within the coral dermis have been lost (see picture below). In that context, the FP layer can be considered the last line of defence for severely bleached corals during a marine heat wave. Much more than a sun-protection layer, the FP layer could help enhance resistance of corals to mass-bleaching...read more about coral bleaching here.

Although beautiful, fluorescence in this picture reveals corals under great thermal stress. During a process called coral-bleaching these corals have lost all their natural skin pigments, revealing the natural fluorescent protein layer (FP) within their tissue. photo: People4Ocean.